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Biomedical subjects

C V Gay

Publications and source records attributed to C V Gay.

84 records · Page 5Linked to original sources
PubMed1981

Development of a procedure for autoradiographic localization of carbonic anhydrase at the electron microscope level.

A method for preparing tissue suitable for electron microscope autoradiographic localization of carbonic anhydrase is described. Radioactivity is in the form of 3H-acetazolamide, a specific inhibitor of carbonic anhydrase. Tissues fixed in glutaraldehyde, dehydrated in ethylene glycol followed by cellosolve as a transition fluid, and embedded in epoxy resin, were found to retain most (74%) of the label. Electron micrographs of avian gastric mucosa prepared in this manner are shown. Other methods of preparation were explored and resulted in considerable losses of label or in inadequately preserved tissue. Light microscope autoradiographic localization of gastric mucosa, shell gland, chorioallantoic membrane, and skeletal muscle compare well with previous localizations.

Acetazolamide↗
PubMed1980

Autoradiographic localization of carbonic anhydrase in the developing chorioallantoic membrane.

Carbonic anhydrase was localized in the chorioallantoic membrane with labeled inhibitor autoradiography of 3H-acetazolamide at 11, 14 and 19 days of incubation. At 11 days carbonic anhydrase was present in low amounts only in the undifferentiated ectoderm cells. At 14 and 19 days, the enzyme was found in increased amounts in all three germ layers of the chorioallantois. In the chorionic ectoderm the villous cavity cells contained the highest level of carbonic anhydrase. This finding lends support to the theory of H+ production to solubilize the CaCO3 of the egg shell. Sinus covering cells showed a considerable lower concentration of the enzyme than did villous cavity cells. Carbonic anhydrase in these cells may be multifunctional, assisting in calcium transport, subserving HCO3- transport from egg shell to blood, and supporting gaseous exchange. In the allantoic endoderm carbonic anhydrase was found in granule-rich cells and might be involved in the transport of Na+ and Cl- ions from allantoic fluid into the blood. The enzyme in the undifferentiated endoderm cells may have a respiratory function. In the mesoderm carbonic anhydrase was detected in the endothelium and pericytes of blood vessels where it is interpreted to support respiratory function.

Allantois↗
PubMed1977

The ulstrastructure of the extracellular phase of bone as observed in frozen thin sections.

The fine structure of the extracellular phase of avian medullary bone and embryonic chick femur was examined in thin sections prepared by ultracryotomy and ultramicroincineration. Since contact with solutions was completely avoided, little or no loss or dislocation of mineral constituents could occur. Amorphous bone mineral (ABM) was present in two forms: as 15-30 nm spheres and as a structure-free haze. Removal of all organic material by low temperature ashing left the ABM intact. Crystals were usually associated with the ABM. In newly ossifying regions clusters or nodules of randomly oriented crystals and ABM appeared to coalesce when they reached approximately 1 micron in diameter. In highly calcified regions crystals appeared to be oriented along collagen fibers. ABM did not appear to be associated with collagen. Unmineralized collagen was visible in osteoid after staining with dry OsO4 vapor and it appeared to be diverted around nodules. Structures which resembled matrix vesicles were present. Selected area electron diffraction patterns indicated the presence of hydroxyapatite.

Animals↗
PubMed1977

Matrix vesicles in newly synthesizing bone observed after ultracryotomy and ultramicroincineration.

Matrix vesicles were observed in femurs of 8-day-old chick embryos prepared by ultracryotomy. Some of the sections were subjected to ultramicroincineration. The unfixed tissues never came into contact with solutions, and thereby artifacts due to dissolution, redistribution, or rearrangement of the mineral constituents were avoided. In the osteoid, electron dense objects with the size and appearance of matrix vesicles were seen, although limiting membranes were not visible. After ultramicroincineration the vesicles were observed to contain small crystals and a less dense amorphous mineral material which may te the precursor of bone mineral. In addition, a ring of ash enclosed the crystalline and amorphous mineral and appeared to occupy the position of the vesicle membrane as seen in conventionally prepared material.

Animals↗
PubMed1974

Carbonic anhydrase and osteoclasts: localization by labeled inhibitor autoradiography.

Autoradiography with tritiated acetazolamide indicates that osteoclasts of the hen and chick contain concentrations of carbonic anhydrase which are similar to those in pancreatic acinar cells. Grain counts of osteoblasts and osteocytes were not different from background. Thus, a sufficient quantity of carbonic anhydrase seems to be present in osteoclasts to be of physiological importance in bone resorption.

Acetazolamide↗
PubMedDate not supplied

Carbonic anhydrase activity in isolated osteoclasts.

Osteoclasts were isolated from the long bones of chicks by a nylon mesh filtering system. The cell purity, in terms of area of the slide occupied, was on the average 77.5% osteoclasts, 22% aggregated osteoblasts and matrix debris, and 1.5% individual blood and marrow cells. Viability, as measured by cytochalasin-blockable phagocytosis, of up to 99% was obtained. Electron microscopic examination revealed good retention of ultrastructural features. The presence of carbonic anhydrase and acid phosphatase in osteoclasts was verified by selective staining methods; the aggregates were positive for alkaline phosphatase. Carbonic anhydrase activity was 0.89 +/- 0.13 X 10(-4) micro Wilbur-Anderson units per osteoclast, and red blood cells had 0.12 +/- 0.03 X 10(-4) units/cell. Neither calcitonin nor parathyroid hormone influenced the activity of carbonic anhydrase. A review of other hormonal effects on carbonic anhydrase is provided.

Animals↗
PubMedDate not supplied

Tritiated thymidine uptake in chondrocytes of chickens afflicted with tibial dyschondroplasia.

3H-Thymidine was localized in sections of growth-plate cartilage and associated tibial dyschondroplastic lesion by autoradiography. One hour after 3H-thymidine was injected, radioactivity was found in the proliferating zone; after 48 hr it was also in the hypertrophic zone, and by 96 hr it was present in cells that were 4 to 5 mm into the lesion. This indicates that the lesion develops from the growth plate itself. The life span of the cells in the growth plate appears to be about 48 hr.

Animals↗
PubMedDate not supplied

Activities and distribution of alkaline phosphatase and carbonic anhydrase in the tibial dyschondroplastic lesion and associated growth plate of chicks.

The tibial dyschondroplastic lesion and associated growth plate were examined for the presence of alkaline phosphatase, an enzyme important in cartilage mineralization, and carbonic anhydrase, an enzyme that regulates acid-base balance of many tissues including cartilage. By histochemistry, both enzymes were found to be present in the prehypertrophic and hypertrophic zones of the growth plate as occurs normally. Enzyme activity was normal or close to normal in the growth plate. Activity was diminished to half of the normal values in the proximal lesion and to zero in the distal lesion. The enzymes are believed to be diminished by necrotic and autolytic processes and are not involved in initiating the formation of the lesion.

Alkaline Phosphatase↗